In today's global economy, transportation of products, units, or goods is a concern for manufactures, suppliers, and others. Many products are shipped internationally, which requires either ocean voyage or air transportation. The weight of the product, the urgency of delivery of the product (e.g., hours or days verses weeks or months), as well as other concerns can dictate the shipping method.
Regulations related to commodities have been implemented especially where those commodities are considered dangerous goods. The definition of dangerous goods are commodities that, when transported, create at least some amount of danger to people, animals, the environment, and/or the carrier of those goods.
Some products deemed dangerous goods might be available for shipment based on certain circumstances. For example, current air shipment regulations state that any package that has a magnetic field greater than 5.25 milli Gauss at a distance of fifteen feet from the surface of the package anywhere along the 360° cannot be shipped by air. However, the product can be shipped by air if the product is packaged to be below 5.25 milli Gauss. If the magnetic field is below 5.25 milli Gauss at fifteen feet, but above two milli Gauss at seven feet anywhere along the 360°, the package can be shipped, but must be labeled as magnetic. If the magnetic field is below two milli Gauss at seven feet anywhere along the 360°, the product can be shipped without labeling or any other restrictions. In the situation where the package can be shipped but must be labeled as magnetic, transportation costs (e.g., air freight) are increased. For example, air freight costs can be increased four, five, or more times than the typical cost to ship a product that is not labeled as magnetic.
Machines and/or systems that utilize linear or rotary motors with permanent magnet assemblies, which are not closed volume geometries, can exhibit remnant static leakage that is below 5.25 milli Gauss at fifteen feet, but above two milli Gauss at seven feet. Thus, these machines and/or systems, to be shipped by air, are required to be labeled as magnetic. There are also a number of other products or goods that exhibit remnant static leakage above certain thresholds and thus are required to have the magnetic labeling.
The earth's magnetic field is about 500 milli Gauss and, thus, a target direct current field should be below two milli Gauss. Since each object in the universe can be considered a potential magnetic dipole, there are multiple sources of potential magnetic field generators that can hinder achievement of a low magnetic field of two milli Gauss or less.